It is known in the art that DICY has the disadvantages of low Tg and poor heat resistance of laminate (measured by DSC, Tg=140° C.) during PCT when it is used as a hardening agent for epoxy resin.
It is known in the art that Benzoxazine (Bz) resin is used as a hardening agent for epoxy resin. But Benzoxazine resin requires a co-hardening agent to open the benzoxazine ring and then crosslink with an epoxy resin. CN1088727C by HITACHI KASEI IND CO LTD teaches the synergistic effect of phenolic resin and Bz resin. However, the use of phenolic resin results in too high dielectric properties (Dk about 4.4, Df about 0.014@2 GHz) and is impossible to meet the regulation requirement of a low dielectric copper clad laminate.
In order to attain low dielectric properties of a copper clad laminate (D≦4.1, Df≦0.01@2 GHz). In the prior art people generally uses expensive cyanate ester resins. The cost of the material for making cyanate ester resins is about more than 8 times of epoxy resin. Thus the product is not competitive due to high cost.
In summary, there is no resin composition that can attain low dielectric properties and high laminate heat resistance without using cyanate ester resin in the art.
Therefore, there is an urgent need for a resin composition that can attain low dielectric properties and high laminate heat resistance without using cyanate ester resin.